// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_BROWSER_STORAGE_PARTITION_IMPL_MAP_H_
#define CONTENT_BROWSER_STORAGE_PARTITION_IMPL_MAP_H_

#include <map>
#include <memory>
#include <string>

#include "base/callback_forward.h"
#include "base/containers/hash_tables.h"
#include "base/gtest_prod_util.h"
#include "base/macros.h"
#include "base/supports_user_data.h"
#include "content/browser/storage_partition_impl.h"
#include "content/public/browser/browser_context.h"

namespace base {
class FilePath;
class SequencedTaskRunner;
} // namespace base

namespace content {

class BrowserContext;

// A std::string to StoragePartition map for use with SupportsUserData APIs.
class CONTENT_EXPORT StoragePartitionImplMap
    : public base::SupportsUserData::Data {
public:
    explicit StoragePartitionImplMap(BrowserContext* browser_context);

    ~StoragePartitionImplMap() override;

    // This map retains ownership of the returned StoragePartition objects.
    StoragePartitionImpl* Get(const std::string& partition_domain,
        const std::string& partition_name,
        bool in_memory);

    // Starts an asynchronous best-effort attempt to delete all on-disk storage
    // related to |site|, avoiding any directories that are known to be in use.
    //
    // |on_gc_required| is called if the AsyncObliterate() call was unable to
    // fully clean the on-disk storage requiring a call to GarbageCollect() on
    // the next browser start.
    void AsyncObliterate(const GURL& site, const base::Closure& on_gc_required);

    // Examines the on-disk storage and removes any entires that are not listed
    // in the |active_paths|, or in use by current entries in the storage
    // partition.
    //
    // The |done| closure is executed on the calling thread when garbage
    // collection is complete.
    void GarbageCollect(
        std::unique_ptr<base::hash_set<base::FilePath>> active_paths,
        const base::Closure& done);

    void ForEach(const BrowserContext::StoragePartitionCallback& callback);

private:
    FRIEND_TEST_ALL_PREFIXES(StoragePartitionConfigTest, OperatorLess);
    FRIEND_TEST_ALL_PREFIXES(StoragePartitionImplMapTest, GarbageCollect);

    // Each StoragePartition is uniquely identified by which partition domain
    // it belongs to (such as an app or the browser itself), the user supplied
    // partition name and the bit indicating whether it should be persisted on
    // disk or not. This structure contains those elements and is used as
    // uniqueness key to lookup StoragePartition objects in the global map.
    //
    // TODO(nasko): It is equivalent, though not identical to the same structure
    // that lives in chrome profiles. The difference is that this one has
    // partition_domain and partition_name separate, while the latter one has
    // the path produced by combining the two pieces together.
    // The fix for http://crbug.com/159193 will remove the chrome version.
    struct StoragePartitionConfig {
        const std::string partition_domain;
        const std::string partition_name;
        const bool in_memory;

        StoragePartitionConfig(const std::string& domain,
            const std::string& partition,
            const bool& in_memory_only)
            : partition_domain(domain)
            , partition_name(partition)
            , in_memory(in_memory_only)
        {
        }
    };

    // Functor for operator <.
    struct StoragePartitionConfigLess {
        bool operator()(const StoragePartitionConfig& lhs,
            const StoragePartitionConfig& rhs) const
        {
            if (lhs.partition_domain != rhs.partition_domain)
                return lhs.partition_domain < rhs.partition_domain;
            else if (lhs.partition_name != rhs.partition_name)
                return lhs.partition_name < rhs.partition_name;
            else if (lhs.in_memory != rhs.in_memory)
                return lhs.in_memory < rhs.in_memory;
            else
                return false;
        }
    };

    typedef std::map<StoragePartitionConfig,
        std::unique_ptr<StoragePartitionImpl>,
        StoragePartitionConfigLess>
        PartitionMap;

    // Returns the relative path from the profile's base directory, to the
    // directory that holds all the state for storage contexts in the given
    // |partition_domain| and |partition_name|.
    static base::FilePath GetStoragePartitionPath(
        const std::string& partition_domain,
        const std::string& partition_name);

    // This must always be called *after* |partition| has been added to the
    // partitions_.
    //
    // TODO(ajwong): Is there a way to make it so that Get()'s implementation
    // doesn't need to be aware of this ordering?  Revisit when refactoring
    // ResourceContext and AppCache to respect storage partitions.
    void PostCreateInitialization(StoragePartitionImpl* partition,
        bool in_memory);

    BrowserContext* browser_context_; // Not Owned.
    scoped_refptr<base::SequencedTaskRunner> file_access_runner_;
    PartitionMap partitions_;

    // Set to true when the ResourceContext for the associated |browser_context_|
    // is initialized. Can never return to false.
    bool resource_context_initialized_;

    DISALLOW_COPY_AND_ASSIGN(StoragePartitionImplMap);
};

} // namespace content

#endif // CONTENT_BROWSER_STORAGE_PARTITION_IMPL_MAP_H_
